Please, stop pluralizing "BSD's", every BSD it's different and OpenBSD only reuses Linux drivers for KMS/DRM; FreeBSD has special layers and tons of drivers ported and NetBSD it's closer to philosophy in design.
So GNU/Linux now it's in the same group as FreeBSD as it has ZFS? Because neither NetBSD nor OpenBSD have it.
OpenBSD doesn't 'rely' on Linux drivers, thanks. Just a shim against KMS/DRM, everything else it's either homegroup or sometimes adapted (back and forth) from NetBSD but OFC patched for correctness and security. There's no ALSA. Pulse it's totally optional. There's no wpa_supplicant except for Eduroam or simlar niche crap under OpenBSD.
OpenBSD has OSS and sndiod. There's Xenocara, an X11 fork.
Again, not Linux, X11, MESA and Gallium are damn generic. Show me the rest of ported Linux drivers into OpenBSD, please.